Isaac the Syrian.

He was born in Nineveh in the 6th century. He entered the monastery as
a youth. Having perfected himself and succeeding in good deeds, he isolated
himself in a desert cave to maintain silence, heeding only to himself and God.
After a number of years, God summoned him to serve as the ruling bishop of the NinevehChurch. However, after being tonsured, Saint Isaac did not remain
very long at his cathedra. This occurred because of the disobedience of a
moneylender, who refused to act according to the Gospel. The Saint thought:
"If they are not obeying Godís directives in the Gospel, then what remains
for me to do here?" He returned to his beloved hermitage in the desert.
Here he lived in silence up to his death, abiding in deeds of self-denial, in
struggles with the flesh and temptations of the demons.

Saint Isaac wrote much, relying on his vast
spiritual experiences. His instructions came to us in the form of 91 homilies.
He reposed in the 6th century.